非球面镜是指表面不是球面或者柱面的透镜。在摄影里，包含非球面光学组件的透镜被称作“非球面镜”。

相比简单透镜，非球面镜的复杂表面可以减少或者消除球差或者其他像差。单一非球面镜可以替代很多的复杂球面镜系统。这样的系统设计会更小，更轻，甚至有时候会更便宜。非球面镜组件被用来设计多光学组件的广角镜或者标准镜头，以此来减少像差。它们也可以和反射光学组件相结合，如施密特修正板，这种非球面镜就被用在施密特摄星仪、施密特-卡塞格林望远镜中。小的模铸非球面镜通常可以用来准直激光二极管。

非球面镜也通常被用来制造眼镜。这种设计可以使眼镜更薄，同时观察者会感到戴眼镜的人眼睛变形更小。非球面眼镜并不会比“最优形式”球面眼镜有更好的视觉效果，不过在没有降低光学性能的条件下，使眼镜厚度更薄，表面更平。

An aspheric lens or asphere is a lens whose surface profiles are not portions of a sphere or cylinder. In photography, a lens assembly that includes an aspheric element is often called an aspherical lens.

The asphere's more complex surface profile can reduce or eliminate spherical aberration and also reduce other optical aberrations such as astigmatism, compared to a simple lens. A single aspheric lens can often replace a much more complex multi-lens system. The resulting device is smaller and lighter, and sometimes cheaper than the multi-lens design. Aspheric elements are used in the design of multi-element wide-angle and fast normal lenses to reduce aberrations. They are also used in combination with reflective elements (catadioptric systems) such as the aspherical Schmidt corrector plate used in the Schmidt cameras and the Schmidt-Cassegrain telescopes. Small molded aspheres are often used for collimating diode lasers.